I would recommend that you look on Houzz.com under products. Otherwise, check Craigs list, Ebay, etc if you want an on line. OR keep hitting those second hand shops!!!
I do not believe yours is an antique or vintage, but an elaborate repro (from what I can tell from the picture). I have a huge chandelier in my formal with 18 arms in much the same style and it is a repro. (An original was too costly and 3 x heavier!)